If you died 200 years ago in America, your family would wash and dress your body and place it in a bed surrounded by candles to dampen the smell of decomposition.

Your immediate family and friends would visit your house over the course of the next week, few needing to travel very far, paying their respects at your bedside. Before the body’s putrefaction advanced too far, the local carpenter would make a simple pine casket, and everyone would gather...